I tested it yesterday, it seems that items stay in your storage only for the time the game is running, so you can exchange items between your own characters. But as soon as you exit the game they are gone (just as if they were not saved along your other data...).

I tested it yesterday, it seems that items stay in your storage only for the time the game is running, so you can exchange items between your own characters. But as soon as you exit the game they are gone (just as if they were not saved along your other data...).